1. Technical Field
The invention relates to liquid ejection inspecting apparatuses, printing apparatuses, and liquid ejection systems.
2. Related Art
Among known printing apparatuses which eject ink to various types of media including paper, cloth, and films for printing are inkjet printers. Inkjet printers have a head which is capable of relative movement with respect to a medium and is provided with nozzle rows of respective colors such as cyan (C), magenta (M), yellow (Y), and black (K). For printing, the nozzles in each of the nozzle rows eject ink to form dots on the medium.
In such inkjet printers, nozzles can be clogged up due to adhering ink or the like, failing to eject ink normally. If ink is no longer ejected from the nozzles normally, problems may occur since dots cannot be formed on the medium properly and images cannot be printed finely.
Various types of methods have heretofore been proposed for inspecting whether or not ejection of ink is being performed normally. Among the inspecting methods proposed is one for detecting the ink ejected from the nozzles optically (see, for example, JP-A-2000-233520). In this inspecting method, whether or not ink is ejected from a nozzle is inspected by detecting, with a photodiode, whether or not a beam emitted from an LED is interrupted by the ink ejected from the nozzles.
Nevertheless, such an inspecting method requires a laser irradiation device of huge size for the sake of laser beam irradiation. This has caused another problem since it is extremely difficult to secure a space for installing the laser irradiation device inside a printer, with a significant increase in cost. Under such circumstances, an ejection inspecting apparatus having more simple, compact configuration, neither requiring much installation space nor causing a large increase in cost, has thus been desired strongly.